Windows Styles Explained

Casement Windows‍

Traditionally windows have been referred to as lights, and the term 'fixed light' is still used to describe a window or part of one that does not open. The part that opens - the sash - is a separate glazed frame that either slides vertically or is hinged on one edge. Hinged windows are often referred to as casements'. In some instances a single sash pivots horizontally; this type is commonly found in roof windows.

Of all the various types of window, the simple hinged or casement window is the most widely supplied by Homesealed in areas around Scotland. Traditional casement window frames made of wood are constructed in much the same fashion as a doorframe. A vertical jamb at each side of the frame is joined by means of mortise-and-tenon joints to the head member at the top and a sill at the bottom.

Depending on the size of the window, the frame is sometimes divided vertically by a mullion or horizontally by a transom.

Modern window frames are sometimes fitted with trickle ventilators that provide a constant supply of fresh air.

A side-hung casement window is usually attached with butt hinges, but sometimes 'easy-clean' extension hinges are used instead, in order to give better access to the outside of the glass for cleaning. A cockspur, or lever fastener, holds the casement closed. A casement stay fixed to the bottom rail holds the window open in various positions. With a top-hung casement, the stay also secures the window in the closed position.

Glazing bars - lightweight moulded strips of wood - are often fitted to divide the glazed areas into smaller panes.

Mild-steel casement windows have slim welded frames and sashes. They are strong and durable, but will rust unless protected by galvanizing or a primer.

Modern versions are galvanised, using a hot-dip process, then finished with a coloured polyester coating.

‍

Sash Windows

Vertically sliding windows are usually known as sash windows. When both the top and bottom sash can be opened, they are known as double-hung sash windows.

Traditional wooden sash windows are constructed with a box frame in which the jambs are made up from three boards - the pulley stile and the inner and outer linings. A back lining completes the box that houses the sash counterweights.

The head is made up in a similar way but without the back lining, and the sill is cut from solid wood. The pulley stiles are jointed into the sill, and the linings are set in a rebate.

The sashes of a double-hung window are held in tracks formed by the outer lining, a parting bead and an inner staff bead. Both beads can be removed in order to service the sash mechanism.

Each sash is counterbalanced by two cast-iron or lead weights - one at each side - which are attached by strong cords or chains that pass over pulleys in the stiles. Access to the weights is through pockets - removable pieces of wood set in the lower part of the stiles.

The top sash slides in the outer track and overlaps the bottom sash at their horizontal meeting rails. The closing faces of the meeting rails are bevelled, and their wedging action helps to prevent the sashes rattling. This also allows both rails to part easily as the window is opened, and improves security when it is locked. The sashes are secured by two-part fasteners of various types, which are screwed to the meeting rails.
‍

‍Window frames

Previously most frames and sashes were made up from moulded sections of solid wood

However, steel-reinforced plastic, mild steel and aluminium are also now used by Homesealed

Metal frames are often fixed to the masonry by means of wooden subframes.

‍
Spiral balances

Modern wooden, aluminium or plastic sliding sashes have spring-assisted spira balances. The balances are fixed to the faces of the frame stiles.

‍

Pivot Windows

Pivot windows are constructed in a similar way to casement windows, but the special hinge mechanism allows the sash to be rotated so that both sides of the glass can be cleaned from inside. Using the built-in safety catch, the sash can be locked when ajar or when fully reversed.

Similar pivoting windows are made for installing in pitched roofs with slopes between 15 and go degrees. The windows are usually double glazed with sealed units, and ventilators are incorporated in the frame or sash. The wood is protected on the outside by a metal covering, and a flashing kit provides a weatherproof seal between the window and roof.

‍

Aluminium Windows

Aluminium window frames first became popular in the 196os as a taste developed for uncluttered 'picture windows'. They were fitted in new houses, and were also widely used to replace existing wooden windows in older homes. They suffered badly from condensation, both on the glass and on the frames, which were excellent conductors of heat and cold. They are now obsolete, but some remain in use.

To overcome these problems, the frames were engineered into complex sections to hold double-glazed sealed units and to incorporate integral draught strips. The hollow sections were filled with insulation material to act as a thermal break, so greatly reducing the condensation problems. This type was usually installed in a wooden subframe.

Plastic (uPVC) windows

Plastic windows are similar in style to aluminium ones, but have thicker sections and incorporate internal steel reinforcement. They are typically made in white or wood-coloured plastic and, once installed, require only minimal maintenance. They are widely used both in new buildings and as replacement windows in older homes.

‍

If you are located in Scotland, get in touch with the Homesealed sales team for the best advice for new windows in your home.

‍

‍